Put very simply:
When you’re asleep, your body becomes paralyzed to prevent stuff like sleep walking, i.e. acting upon our dreams. It’s self preservation.
Sleep paralysis is when you wake up but your body hasn’t turned off its paralysis so you become aware of the fact you can’t move. This of course triggers panic. The fact that you’re half asleep and scared can trigger hallucinations.
I had it for years and rarely ever get it anymore because I stopped being scared of it.
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